The crew aboard the Boeing CST-100 Starliner received encouraging news regarding their eventual return to Earth. Recently, Earth-based testing of the spacecraft’s thrusters was completed, which had left the spacecraft stranded in orbit since early June. Boeing and NASA had been awaiting the results of these tests to start planning the Starliner’s homeward journey.
An update provided late last week noted, “Ground testing of a Starliner Reaction Control System (RCS) thruster at the White Sands Test Facility in New Mexico is complete, and teams are now turning their attention to data reviews.” The purpose of this testing was to assess thruster degradation to understand why some thrusters were offline during the flight and to evaluate the potential impact of reactivating those thrusters on the Crew Flight Test.
The term “de-selected” refers to thrusters that ceased functioning. Prior to and during the Starliner’s launch, the helium tanks that control the thrusters experienced leaks, causing several delays. Officials mentioned last month that while the ship has 70 hours’ worth of helium capacity, it only requires seven hours for its operations. They indicated earlier this month that while the spacecraft could return immediately if necessary, they are not yet fully prepared for that eventuality.
In the latest update, NASA and Boeing hinted that a return flight could occur by the end of this month. However, the timeline now appears less specific: “Boeing and NASA engineers will proceed with thruster disassembly and inspections, and will continue finalizing flight rationale in support of readiness reviews for Starliner’s nominal return to Earth with commander Butch Wilmore and pilot Suni Williams in the coming weeks.”